1. Field of the Invention
This invention relates to the storage of hot bituminous asphalt and like material, and to improvements in the construction of silos of the type normally used in the industry for the storage of such materials.
2. Description of the Prior Art
A basic problem in the storage of bitumen is the segregation of materials in the mixed condition caused by the method of storage and "angle of respose" of asphalt mixes in containers and angled or cylindrical silos used conventionally in the industrial use of asphalt. The separation of course and fine materials in a mix results in a loss of compact homogeneous qualities leading to porous, weak and sub-standard road paving materials due to aeration and separation.
The above difficulties result, at least partially, from the conventional method of depositing asphalt into silos. Thus, conventional handling is in such a manner that as the asphalt mix falls, it deposits in a more or less conical form. Thus, the asphalt within the silo forms a pile that is higher in the centre than it is at its edges. On the other hand, as the material falls out of the silo for use, the material tends to flow from the centre of the pile only, due to the fact that the outlet from the silo is central. Since the natural pattern of materials dropped in a continuous stream on a conical pile is for the coarser component of the material to migrate to the outside of the pile and the finer material to stay in the centre, then it follows that the material will flow from the silo in an uneven manner leading to inconsistency of texture when the product is finally laid in road paving operations.
Among proposals for dealing with the above difficulties are those disclosed in Canadian Pat. No. 784,409 granted on May 7, 1968, to J. S. Eaton. Eaton proposed to feed asphalt from a conveyor into a silo through a rotatable silo top so that the mix would fall into the silo in a uniform thickness blanket eliminating "coning up." Eaton also provided an adjustable cone near the discharge of the silo so that the material would fall out of it in a uniform manner again to hold segregation of the mix to a minimum.
The unit proposed by Eaton, however, is unnecessarily complex and expensive since it is necessary to provide a mechanically rotatable top to achieve the desired uniform deposition of the material within the silo.